Brussels | ITP-2025-1 | Preeti Tyagi | Week 8 | Sprint 2 implement and fix tests

Sprint-2/debug/address.js

@@ -12,4 +12,8 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+/*console.log(`My house number is ${address[0]}`);*/
+
+console.log(`My house number is ${address.houseNumber}`);
+
+

Sprint-2/debug/author.js

@@ -11,6 +11,11 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
+/*for (const value of author) {
+  console.log(value);
+}*/
+
+for (const value of Object.values(author)) {
   console.log(value);
 }
+

Sprint-2/debug/recipe.js

@@ -12,4 +12,5 @@ const recipe = {
 
 console.log(`${recipe.title} serves ${recipe.serves}
   ingredients:
-${recipe}`);
+/*${recipe}`);*/  //incomplete instructions, To show data inside we need to add more properties
+${recipe.ingredients.join(", ")}`);

Sprint-2/implement/contains.js

@@ -1,3 +1,8 @@
-function contains() {}
+function contains(obj, property) {
+  if (obj === null || typeof obj !== "object" || Array.isArray(obj)) {
+    return false;
+  }
+  return Object.hasOwn(obj, property);
+}
 
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -16,20 +16,40 @@ as the object doesn't contains a key of 'c'
 // Given a contains function
 // When passed an object and a property name
 // Then it should return true if the object contains the property, false otherwise
-
+test("returns true when object contains the property", () => {
+  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
+  expect(contains({ name: "Alice", age: 25 }, "age")).toBe(true);
+  expect(contains({ g: "p", m: 1 }, "t")).toBe(false);
+});
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+test("contains on empty object returns false", () => {
+  expect(contains({}, "a")).toBe(false);
+});
 
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("returns true for existing property", () => {
+  expect(contains({ a: 1, b: 2, c: 3 }, "c")).toBe(true);
+});
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("returns false for non-existent property", () => {
+  expect(contains({ a: 1, b: 2 }, "z")).toBe(false);
+});
 
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+
+test("returns false for invalid parameters", () => {
+  expect(contains([], "a")).toBe(false);
+  expect(contains(null, "a")).toBe(false);
+  expect(contains(undefined, "a")).toBe(false);
+  expect(contains(42, "a")).toBe(false);
+  expect(contains("notAnObject", "a")).toBe(false);
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,9 @@
-function createLookup() {
-  // implementation here
+function createLookup(pairs) {
+  if (!Array.isArray(pairs)) {
+    throw new Error("Input must be an array of pairs");
+  }
+
+  return Object.fromEntries(pairs);
 }
 
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,6 +1,6 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
+//test.todo("creates a country currency code lookup for multiple codes");
 
 /*
 
@@ -33,3 +33,26 @@ It should return:
    'CA': 'CAD'
  }
 */
+
+test("creates a country currency code lookup for multiple codes", () => {
+  const pairs = [
+    ["US", "USD"],
+    ["CA", "CAD"],
+  ];
+
+  const expected = {
+    US: "USD",
+    CA: "CAD",
+  };
+
+  expect(createLookup(pairs)).toEqual(expected);
+});
+
+test("returns an empty object for an empty array", () => {
+  expect(createLookup([])).toEqual({});
+});
+
+test("throws an error for invalid input", () => {
+  expect(() => createLookup(null)).toThrow(Error);
+  expect(() => createLookup("not an array")).toThrow(Error);
+});

Sprint-2/implement/querystring.js

@@ -1,16 +1,31 @@
-function parseQueryString(queryString) {
-  const queryParams = {};
-  if (queryString.length === 0) {
-    return queryParams;
-  }
-  const keyValuePairs = queryString.split("&");
-
-  for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
-  }
-
-  return queryParams;
+function parseQueryString(query) {
+  const result = {};
+  if (!query) return result;
+
+  if (query.startsWith("?")) query = query.slice(1);
+  if (!query) return result;
+
+  query.split("&").forEach(pair => {
+    if (!pair) return;
+
+    const [key, value = ""] = pair.split("=");
+    const k = key.replace(/\+/g, " ");
+    const v = value.replace(/\+/g, " ");
+
+    if (result[k]) {
+      result[k] = [].concat(result[k], v);
+    } else {
+      result[k] = v;
+    }
+  });
+
+  return result;
+}
+
+module.exports = parseQueryString;
+
+
+  return result;
 }
 
 module.exports = parseQueryString;

Sprint-2/implement/querystring.test.js

@@ -10,3 +10,23 @@ test("parses querystring values containing =", () => {
     "equation": "x=y+1",
   });
 });
+
+test("parses multiple key-value pairs", () => {
+  expect(parseQueryString("a=1&b=2")).toEqual({ a: "1", b: "2" });
+});
+
+test("handles empty query string", () => {
+  expect(parseQueryString("")).toEqual({});
+});
+
+test("handles values with multiple =", () => {
+  expect(parseQueryString("formula=a=b=c=d")).toEqual({ formula: "a=b=c=d" });
+});
+
+test("handles keys with no value", () => {
+  expect(parseQueryString("flag")).toEqual({ flag: "" });
+});
+
+test("handles multiple & with some empty pairs", () => {
+  expect(parseQueryString("a=1&&b=2&c")).toEqual({ a: "1", b: "2", c: "" });
+});

Sprint-2/implement/tally.js

@@ -1,3 +1,9 @@
-function tally() {}
+function tally(arr) {
+  const result = {};
+  for (const item of arr) {
+    result[item] = (result[item] || 0) + 1;
+  }
+  return result;
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -20,15 +20,35 @@ const tally = require("./tally.js");
 // When passed an array of items
 // Then it should return an object containing the count for each unique item
 
+test("returns an object with counts for each unique item", () => {
+  expect(tally(["a", "a", "b", "c"])).toEqual({ a: 2, b: 1, c: 1 });
+  expect(tally(["cow", "goat", "cow", "fox"])).toEqual({
+    cow: 2,goat: 1,fox: 1,
+  });
+});
+
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
+
+test("tally on an empty array returns an empty object", () => {
+  expect(tally([])).toEqual({});
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
 
+test("tally returns counts for each unique item", () => {
+  expect(tally(["a", "a", "b", "c"])).toEqual({ a: 2, b: 1, c: 1 });
+  expect(tally(["x", "x", "x"])).toEqual({ x: 3 });
+});
+
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+
+test("throws an error for invalid input", () => {
+  expect(() => tally("not an array")).toThrow("Input must be an array");
+  expect(() => tally(123)).toThrow("Input must be an array");
+});

Sprint-2/interpret/invert.js

@@ -10,20 +10,30 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
   return invertedObj;
 }
 
+module.exports = invert;
+
+const invert = require("./invert.js");
+
 // a) What is the current return value when invert is called with { a : 1 }
+{ key: 1 }
+
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
+{ key: 2 }
+
 
 // c) What is the target return value when invert is called with {a : 1, b: 2}
+{ "1": "a", "2": "b" }
 
 // c) What does Object.entries return? Why is it needed in this program?
-
+returns an array of [key, value] pairs
 // d) Explain why the current return value is different from the target output
 
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+console.log(invert({ a: 1, b: 2 }));